Generally, a rotor in a motor rotates by electromagnetic interaction with a stator. Here, a rotating shaft inserted in the rotor also rotates to generate a rotation driving force.
A sensor module including a magnetic device is disposed inside the motor. The magnetic device identifies a current position of the rotor by sensing a magnetic force of a sensing magnet installed to be interlocked with rotation of the rotor.
Generally, a sensor module includes a sensing plate which rotates in conjunction with a rotating shaft, and a sensing magnet attached to the sensing plate. The sensing magnet may be fixed to the sensing plate using an adhesive, etc.
However, when adhesive strength is weakened between the sensing magnet and the sensing plate due to heat or an impact, a problem in which a rotor position may not be accurately detectable due to relative rotation of the sensing magnet occurs.